Brake pads, brake pad wear sensors, brake rotors

Hot Tip:

Clean brake caliper

Performance Gain:

Proper brake function

Complementary Modification:

Flush brake fluid. Replace brake rotors

You should check your brake rotors with every major service that you perform on your BMW Z3. Inspect your brake rotors for cracks, scoring or replace if you have a pulsation when braking. Brake rotors can look OK and still be worn out. If there is a ridge around the edge of the brake rotor, this is a good sign that they are worn out. Measure brake rotor thickness using a micrometer to determine if they need replacing. When measuring, measure in a few different spots and use lowest number.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Figure 1

Most factory rotors and some aftermarket rotors will have a minimum thickness stamped on the rotor. This will be in area of hat or hub flange. Clean rust away from rotor to uncover specs. There may also be a part number. See our tech article on disc brake specifications for all Z3 model brake specifications. It's a good idea to inspect and replace your brake pads when replacing brake rotors. See our tech article on brake pad replacing. Always replace brake rotors in pairs by the axle. With the vehicle on the ground, loosen each whelk stud about 1/2 turn. This will help with removing them once the vehicle is jacked up. Lift and support axle of vehicle you are replacing brake pads on. See our tech article on jacking up your vehicle. Remove wheels on axle you are replacing brake rotors on.

Pull brake pad wear sensor (green arrow) out of brake pad out of driver side brake pad. Be very careful as sensor tends to break when removed. I like to use a pair of needle nose pliers to pull sensor out.

Using a flathead screwdriver, slowly press brake caliper piston in. This allows brake caliper to be pulled off brake rotor easily. I like to pry between the outer brake pad and brake rotor. This way there is less chance of damaging the caliper piston. Forcing the piston back into the caliper will cause the brake fluid in the reservoir to rise. Be prepared to remove some fluid.

Next, using a 6mm Allen bit, remove brake rotor mounting fastener. (green arrow) Then remove brake rotor from hub. The rotor might be stuck so be prepared to give it a few taps with a mallet. If you are replacing the rear rotor make sure the parking brake is off before trying to remove the rotor.